The invention concerns a switch with devices for selfadjustment when the switch is mounted in a fitting aperture in the supporting in the support plate of a pedal box or similar.
When fitting switches, which are used for checking the positions of brake or clutch pedals as well as for use as brake-light switches or for other purposes problems frequently occur with the adjustment of the switches for a functionally correct method of operation. This applies in particular to accurate adjustment of the switch positions and the contact travel of such switches, in order to allow for the tolerances involved in the manufacture of the pedal box. This has led to the use of push-switches with adjustable lengths, but these frequently fail to satisfy the specified requirements for switching accuracy. Furthermore, the installation and adjustment of such switches is time consuming and thus expensive.
Self-adjusting switches can also be prone to the following problems:
Accidental or unintentional maladjustment during shipment of parts, vehicle assembly or serving; PA1 Fatigue or gradual slackening of the adjustment system; PA1 Maladjustment of the switch due to overtravel of the pedal. PA1 a) the switch has an elongated switch housing with a base and a retention device for fixing the switch to the support plate, PA1 b) there is a switch plunger in the longitudinal axis of the switch housing which can move longitudinally against the action of a spring, PA1 c) the switch has a slider which can move with respect to the switch plunger and surrounds the plunger over part of its length, and is guided with radial vanes in guide grooves parallel to the axis, so that it can move longitudinally up to opposite-lying wall sections of the switch housing, PA1 d) alongside the guide grooves for the slider, there are limit stops arranged in staggered formation in the circumferential direction of the switch housing, between which the slider can be fixed in the axial direction, PA1 e) furthermore, the plunger shank and the inside of the slider are provided with notched tracks with rows of locking teeth parallel to the axis, which intermesh like a comb and fix the switch plunger to the slider in the axial direction when the switch plunger is turned with respect to the slider, PA1 f) the switch plunger together with the switch housing can be rotated about its longitudinal axis with respect to the slider until mutual engagement of the notched tracks take place, PA1 g) on further rotation of the switch plunger with respect to the slider about the longitudinal axis after engagement of the notched tracks, the slider is released from engagement with the limit stops on the switch housing and the base, and thus after adjustment of the length of the plunger shank the slider is guided longitudinally together with the switch plunger in the guide grooves on the switch housing. PA1 The plunger length can be set to the length required simply by inserting the switch into the aperture in the support plate and then rotating it. PA1 As soon as the switch is fixed in the fitting position, its adjustment cannot be changed. PA1 The switch tolerates the pedal travel being exceeded. PA1 fitting is carried out in a single operation and the fitter does not need to move the pedal to and fro for adjustment purposes. PA1 when the switch is removed from the pedal box, the switch is automatically reset to its original length and is ready for further use. PA1 The switch cannot be adjusted or maladjusted during shipment.
This has led to various solutions in the design of quick-fit self-adjusting switches with adjustment protection, but which are frequently unsatisfactory.
The invention is based on the problem of creating a switch of the type described at the outset with devices for self-adjustment during fitting of the switch and with a simple construction, so that it can be mounted on the vehicle in a single operation, in which it is not only fixed in the fitting position but simultaneously also adjusted for functionally correct operation.
This problem is solved with a switch with the following characteristics:
The invention has the advantage that such switches cannot be accidentally or unintentionally maladjusted before they are fitted. The situation is rather that when the switches, with the moving parts of the switches in the initial state as supplied by the manufacturer, are mounted on the vehicle, they are simply inserted in an fitting aperture provided in a suitable support, for example in a pedal box support, in which simultaneously with the fitting procedure the movable switch parts are also automatically adjusted, so that the switch adjustment is already complete after it is fitted.
The decisive factor in this simple fitting procedure with automatic adjustment of the switch during the fitting procedure is that the switch has a slider which moves with respect to the switch plunger; and the slider has radial vanes with which it is moved longitudinally in guide grooves parallel to the axis up to opposite-lying wall sections of the switch housing.
Alongside the guide grooves for the slider, the switch housing and base contains limit stops between which the slider, in the condition as supplied, that is before fitting, is fixed in the axial direction. This slider can be moved longitudinally along a guide piece, which can rotate about the longitudinal axis of the switch housing. The plunger shank and the inside of the slider are also provided with notched tacks with rows of locking teeth arranged parallel to the axis, which intermesh like a comb and fix the switch plunger to the slider in the axial direction when the switch plunger is turned with respect to the slider. The switch plunger is moreover designed so that it cannot rotate in the switch housing, and can thus be rotated about its longitudinal axis together with the switch housing with respect to the slider until the notched tracks engage.
With the switch in the condition as supplied, the guide piece for. the slider is provided at the end with locking cams situated beneath hook-shaped retention lugs on the switch housing. The switch with these retention lugs can be inserted from underneath into a profiled fitting aperture in the pedal box or similar, and locked by simply rotating it about its longitudinal axis in the aperture.
When it is fitted into the fitting aperture, the plunger shank pushes against the flag of a brake or clutch pedal and is thus pressed inwards against the pressure of a return spring into the switch housing up to its adjustment position. When the switch is then rotated about its longitudinal axis, the locking cams held fixed in the appropriately contoured aperture in the support plate, lock the guide piece with the slider against rotation, while the switch housing together with the switch plunger can be turned through an angle of approximately 45.degree. in order to secure the switch in the fitting aperture. Turning the switch housing with the plunger causes the notched tracks on the plunger shank and on the inner circumference of the slider to engage, thereby locking the switch plunger together with the slider in the adjusted position. Further rotation of the housing and the switch plunger together with respect to the slider moreover unlocks the latter at the axial limit stops on the switch housing, allowing it to move in the guide grooves in the switch housing parallel to the axis against the pressure spring for the switch plunger and between switch positions ON and OFF.
This results in the following advantages:
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.